New Hungarian Azhdarchid

["Jaime A. Headden" <qilongia@yahoo.com>]

Since no one has mentioned this here, I'd like to point out that the new issue
of _Acta Palaeontologica Polonica_ is out, and in it, while nothing
spectacularly dinosaurian, are several good papers.

One in particular, Ősi et al., reports on yet another Late Cretaceous
azhdarchid (est. wingspan 3.5m) from Eastern Europe, this time from the
Santonian of Hungary, whereas *Hatzegopteryx* is from the Maastrichian of
Romania.

  Ősi, A., D. B. Weishampel & C. M. Jianu 2005. First evidence of
   azhdarchid pterosaurs from the Late Cretaceous of Hungary.
   _Acta Palaeontologica Polonica_ 50(4):777?787.

Abstract:
  "New remains of an azhdarchid pterosaur were discovered from the
   Upper Cretaceous (Santonian) Csehbánya Formation at the Iharkút
   vertebrate locality in the Bakony Mountains, western Hungary.
   Among the isolated bones, consisting principally of 21
   symphyseal jaw fragments, four cervical vertebrae, a right
   radius, and some fragmentary limb bones, is a complete
   articulated mandible that represents one of the best-preserved
   mandibular material of any presently known azhdarchid
   pterosaur. The complete edentulous jaw, referred to
   *Bakonydraco galaczi* gen. et sp. nov. posesses several
   features diagnostic for azhdarchids which prove that
   *Bakonydraco* belongs to this group. The cervical vertebrae
   exhibit azhdarchid features and consequently are referred to as
   Azhdarchidae indet. The discovery of these fossils helps to
   understand the construction of the azhdarchid mandible and
   provides new insight for studying the feeding style of the
   edentulous azhdarchid pterosaurs."

  The mandible in particular is very similar to one described for
*Queztalcoatlus* sp. (Kellner & Langston, 1996, _JVP_ 16(2):222-231), and even
possesses a symphyseal midline keel and pronounced development of the tomia at
the keel extent on the dorsal surface similar to that seen in *Tapejara*. It
measures 290mm long, roughly 11.5 inches, so this was a small azhdarchid.

  In the same issue, Samman et al. describe the use of morphometic and PCA
analysis using denticle morphology as a component to assess variation in
tyrannosaurid dentition, allowing them to explicitly differentiate point clouds
of various tooth elements, segregated into premaxillary, mesial maxillary,
distal maxillary, mesial dentary, and distal dentary.

  Samman, T., G. L. Powell, P. J. Currie & L. V. and Hills. 2005.
   Morphometry of the teeth of western North American
   tyrannosaurids and its applicability to quantitative
   classification. _Acta Palaeontologica Polonica_ 50(4):757-776.

Abstract:
  "Gross tooth morphology and serration morphology were examined
   to determine a quantifiable method for classifying
   tyrannosaurid tooth crowns from western North America. From the
   examination of teeth in jaws, tyrannosaurid teeth could be
   qualitatively assigned to one of five types based on the
   cross-sectional shape of the base of the tooth and
   characteristics of the mesial carina. A principal component
   analysis (PCA) revealed that much of the variance in tooth
   shape was a result of isometry, but some gross morphological
   variables exhibited strong positive allometry. Non-size
   associated factors were also important in determining tooth
   shape, particularly when data on denticle dimensions were
   considered in the analysis. While PCA identified important
   factors in variation, PCA ordination plots did not cluster the
   teeth into distinct, separate groupings based on taxon or bone
   of origin. The group classification functions determined by
   discriminant analysis, though not universally successful for
   classifying unidentified isolated teeth of all tyrannosaurids,
   do identify bone of origin of adult *Albertosaurus*,
   *Daspletosaurus*, and *Gorgosaurus* teeth at a statistically
   acceptable level."

  Finally, while not especially related to dinosaurs, Evans and Wang describe
the Yixian anguimorph *Dialinghosaurus* Ji, 1998, which shows distinct
ornamentation of the skull roof. 

  Evans, S.E. & Wang Y. 2005. The Early Cretaceous lizard
   *Dalinghosaurus* from China. _Acta Palaeontologica Polonica_
   50(4):725-742.

Abstract:
  "The Early Cretaceous lizard genus *Dalinghosaurus* from the
   Yixian Formation of Liaoning, China, was originally described
   on the basis of a partial postcranial skeleton characterised by
   extremely long slender hind feet and a long tail. The skull has
   remained unknown and the systematic position is undetermined.
   Here we describe the skeletal anatomy of this lizard in detail
   based on a series of new specimens in the collections of the
   Institute of Vertebrate Paleontology and Paleoanthropology,
   Beijing. The adult animal is small, with a well-ossified skull
   having a characteristic pattern of pustulate sculpture on the
   roofing bones and an expanded angular flange on the lower jaw.
   Skin impressions show a pattern of fine granular dorsal scales,
   rhomboidal ventral scales, and elongate tail scales arranged in
   annulae. In many features, the skull resembles that of the
   living *Xenosaurus* and *Shinisaurus*, as well as *Carusia*
   from the Late Cretaceous of Mongolia and China. Phylogenetic
   analysis using three different data sets provides some support
   for that interpretation. The postcranial skeleton is
   characterised by long hind limbs and short forelimbs, but the
   delicacy of the long pes and the slender claws suggest this
   animal may have been a climber rather than a facultative
   bipedal runner."

  What is actually quite spectacular, though, are two specimens from the lower
Yixian beds at Dawangzhangzi, Liaoning Province, IVPP V13865B and IVPP V12586,
which show the details of the squamation, replete from body scales, annular
rings around the tail, and fine scalation around the fifth toe, among other
details. What may be even more spectacular is the absence of a fine collagenous
halo predicted by proponents of the "dinosaurs aren't feathered" studies, which
might be termed DAFt. Even Yixian salamanders show these details in remarkable
concordance to their soft-tissue, such as larval gills, etc., which might be
expected in animals that lacked the excessively-fraying, perturbated collagen
from the skin, as Feduccia et al. and Theagarten-Soliar have recently suggested
is the actual condition.

  In this same issue, there are also an immense number of mammal papers, and a
paper by Grellet-Tinner and Dyke on the eggshell of European *Lithornis*.

  Grellet−Tinner, G. & G. J. Dyke. 2005. The eggshell of the
   Eocene bird *Lithornis*. _Acta Palaeontologica Polonica_
   50(4):831?835.

Abstract:
  "Although the fossil bird *Lithornis* has been known for more
   than a century, only in the 1980s were its affinities within
   the palaeognathous birds (Aves, Palaeognathae) realized and
   demonstrated by use of osteological characters. Other lines of
   evidence could, however, be used to test hypotheses of its
   affinities. To add data to this ongoing investigation, we
   present the first detailed description of the microscopic
   morphology of the eggshell of this fossil bird. Our description
   of eggshells of two species of *Lithornis* is consistent with
   the placement of this fossil bird within Palaeognathae.
   Characters that corroborate this position include the presence
   of three aprismatic structural layers visible by use of
   scanning electron microscopy (SEM) in the eggshell
   microstructure. The placement of *Lithornis* phylogenetically
   close to the extant flighted South American group Tinamidae is
   supported on the basis of characters present in the structural
   composition of the eggshell layers of both these taxa."

  Cheers,

Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


                
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